Bacterial infections are a serious health problem, which is becoming ever more critical with the development of drug resistance in bacterial populations. In the US alone, multi-drug resistant Staphylococcus aureus (MRSA) is blamed for over 18,000 annual deaths, and this organism represents just one of many types of bacteria that are resistant to current treatments. The long term objective of this research is to develop plant based approaches to combat bacterial infection. This particular proposal is focused specifically on the plant goldenseal (Hydrastis canadensis), which is among the top ten best selling herbal medicines in the US. Although clinical trials of goldenseal's efficacy have not been conducted, the plant has shown efficacy against a number of bacteria, including MRSA, in vitro. It has long been assumed that goldenseal's antibacterial activity results from alkaloids that the plant produces, one of which has demonstrated efficacy against infections in clinical trials. However, new data from our laboratory indicate that other constituents are also important. The aims of the proposed research are (1) to identify non-alkaloidal constituents that play a role in goldenseal's antibacterial activity and (2) to determine the mode of action of these constituents. These aims will be accomplished by testing the central hypothesis (based on our strong preliminary data) that non-alkaloidal constituents of goldenseal enhance, or potentiate, the antibacterial activity of this plant's alkaloids by inhibiting bacterial efflux pumps. To test this hypothesis, an innovative approach combining comprehensive constituent profiling with bioassay guided fractionation will be employed. The ultimate goal of these experiments is not to develop single agent treatments from goldenseal, but to demonstrate how the multiple constituents in complex goldenseal extracts interact to inhibit the growth of bacteria. Expertise of the research team in the characterization of complex plant extracts using mass spectrometry will be essential to accomplishing this goal. The rationale for conducting this research is that it is expected to provide insight into appropriate therapeutic use of goldenseal, facilitate standardization of goldenseal products, and serve as a basis for the selection of optimally effective goldenseal preparations for clinical trials. The proposed investigations will be conducted with major involvement from undergraduate students, including females and minorities. PUBLIC HEALTH RELEVANCE: According to CDC estimates, bacterial infections are responsible for the deaths of more than 90,000 US hospital patients every year. The proposed research is relevant to public health because it has the potential to lead to the discovery of new, cost-effective approaches to combat such infections. Furthermore, this research will provide insight into the efficacy of goldenseal (Hydrastis canadensis), a plant that has, thus far, been sparsely researched even though it is among the top ten best selling herbal medicines in the US.